This is an open-label (a medical research study in which participants and researchers are told which treatments the participants are receiving, "unblinded"), multi-center (when more than 1 hospital or medical school team work on a medical research study), non-randomized, single-arm study of paliperidone ER in participants previously treated with risperidone with poor response. The study will consist of 2 phases: a main phase of 6 months and an extension phase of another 6 months. The total duration of the study will be 12 months. All participants will receive an oral (having to do with the mouth) daily dose of paliperidone ER in flexible dosage (in the range of 3-12 milligram [mg]: 3 mg, 6 mg, 9 mg, or 12 mg) according to Investigator's discretion. Efficacy and safety of participants will primarily be evaluated by Positive and Negative Syndrome Scale (PANSS) and Extrapyramidal Symptoms Rating Scale (ESRS), respectively. Participants' safety will be monitored throughout the study.